This invention relates to an apparatus for closing continuously and spacedly advanced cardboard boxes which are open at least at one end and which are provided with an inner lining glued to the box and projecting in the zone of the opening beyond the crease lines of the box flaps. The apparatus includes a wide flap opener for bending outwardly the wide flaps of the box.
Apparatuses of the above-outlined type find particular use in automatic packaging machines for preparing the cardboard boxes for the filling operation and to subsequently perform the lid (flap) closing operation. Thus, in known packaging machines the prefabricated cardboard boxes which are stacked in a flat condition, are introduced into a chain conveyor which advances the boxes through the individual operational stages and eventually forwards the filled and closed package to a machine outlet.
When boxes without inner lining or boxes with lining glued entirely to the cardboard are used, these operations may be performed in a continuous manner. In case of cardboard boxes which have a glued inner lining projecting beyond the flap creases and having non-glued ends, such a continuous operation, however, has not been possible heretofore. The preparation of the boxes for welding the ends of the thermoplastic inner lining had to be performed in a timed sequence for which complex devices with cam discs and control cams were required. Because of structural limitations, the output of these known apparatuses has been relatively small.
In view of the fact, however, that cardboard boxes having outwardly projecting inner linings are used with increasing frequency because of a better seal insured by such linings, the above-noted disadvantages has become important.